Assessing transfer entropy from biochemical data.

We address the problem of evaluating the transfer entropy (TE) produced by biochemical reactions from experimentally measured data. Although these reactions are generally nonlinear and nonstationary processes making it challenging to achieve accurate modeling, Gaussian approximation can facilitate the TE assessment only by estimating covariance matrices using multiple data obtained from simultaneously measured time series representing the activation levels of biomolecules such as proteins. Nevertheless, the nonstationary nature of biochemical signals makes it difficult to theoretically assess the sampling distributions of TE, which are necessary for evaluating the statistical confidence and significance of the data-driven estimates. We resolve this difficulty by computationally assessing the sampling distributions using techniques from computational statistics. The computational methods are tested by using them in analyzing data generated from a theoretically tractable time-varying signal model, which leads to the development of a method to screen only statistically significant estimates. The usefulness of the developed method is examined by applying it to real biological data experimentally measured from the ERBB-RAS-MAPK system that superintends diverse cell fate decisions. A comparison between cells containing wild-type and mutant proteins exhibits a distinct difference in the time evolution of TE while any apparent difference is hardly found in average profiles of the raw signals. Such a comparison may help in unveiling important pathways of biochemical reactions.

Current Driven Tricritical Point in Large-N_{c} Gauge Theory.

We discover a new tricritical point realized only in nonequilibrium steady states, using the AdS/CFT correspondence. Our system is a (3+1)-dimensional strongly coupled large-N_{c} gauge theory. The tricritical point is associated with a chiral symmetry breaking under the presence of an electric current and a magnetic field. The critical exponents agree with those of the Landau theory of equilibrium phase transitions. This suggests that the presence of a Landau-like phenomenological theory behind our nonequilibrium phase transitions.

Expression of p27Kip1 protein in gastric carcinoma.

BACKGROUND/AIMS: p27 protein resulted in the accumulation of cyclin E/cyclin dependent kinase 2/p27 ternary complexes inhibits gap1 to synthesis phase transition. Here, we have investigated the correlations, if any, between the expressions of p27 and p53, and proliferation cell nuclear antigen. METHODOLOGY: A retrospective study was performed on 75 cases of gastric cancer that had undergone surgical resection. Immunohistochemical staining was performed using the avidin-biotin-peroxidase complex technique method, with anti-p27 antibody, anti-p53 antibody and anti-proliferation cell nuclear antigen antibody. RESULTS: The rate of lymph node metastasis in the p27 negative cases was significantly higher than that in the p27 positive cases.The rate of tumor limited to the gastric wall in the p27 positive cases was significantly higher than-that in the p27 negative cases.The mean proliferation cell nuclear antigen index of the p27 negative cases was significantly higher than that of the p27 positive cases. The survival rate of the p27 positive cases was significantly higher than that of the p27 negative cases. In Stage III cases, the survival rate of the p53 negative p27 positive or p53 negative p27 negative cases was significantly higher than that of p53 positive p27 negative cases. CONCLUSIONS: p27 was correlated with lymph node metastasis, depth of invasion, and proliferative activity of gastric cancer. Immunoreactivity of combination of p53 and p27 was a useful predictive marker of prognosis of gastric cancer.

Comparison between the gastric cancer cell line MKN-45 and the high-potential peritoneal dissemination gastric cancer cell line MKN-45P.

Peritoneal metastasis is the most common form of recurrence in gastric cancer, and is associated with a poor prognosis. It is clear that many agents are involved at the various stages of this process, however, many aspects of the progression remain unclear. In the present study we compared the gastric cancer cell line MKN-45 with the high-potential peritoneal dissemination gastric cancer cell line MKN-45P, established from MKN-45. The supernatant of culture medium of MKN-45 cells or MKN-45P cells was collected, and the concentrations of interleukin-1ß (IL-1ß), IL-6, IL-8, hepatocyte growth factor (HGF), Transforming growth factor beta-ß1 (TGF-ß1), vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2), MMP-9, and tissue inhibitor of metalloproteinase-1 (TIMP-1) proteins were measured using an enzyme-linked immuno sorbent assay (ELISA) method. Invasion, wound healing and adhesion assays were performed in vitro to examine interstitial invasion, migration and adhesion in the gastric cancer cell lines. Moreover, Western blotting was performed to determine the expression of cyclooxygenase-1 (COX-1) and COX-2 proteins in the culture media of the cell lines. The concentrations of IL-6, IL-8, VEGF and MMP-2 protein in the culture supernatant of MKN-45P were significantly higher than those of MKN-45. Percent adhesion of MKN-45P was significantly higher than that of MKN-45 in the fibronectin-coated group. There was no significant difference in invasion or migration between MKN-45 and MKN-45P. COX-1 and COX-2 proteins were observed in both cell lines. These results suggested that secretion of IL-6, IL-8, VEGF and MMP-2 from cancer cells, and adhesion of cancer cells to fibronectin, were related to the establishment of peritoneal dissemination.

Prognosis of metastatic splenic hilum lymph node in patients with gastric cancer after total gastrectomy and splenectomy.

AIM: To clarify the significance of combined resection of the spleen to dissect the No. 10 lymph node (LN). METHODS: We studied 191 patients who had undergone total gastrectomy with splenectomy, excluding non-curative cases, resection of multiple gastric cancer, and those with remnant stomach cancer. Various clinicopathological factors were evaluated for any independent contributions to No. 10 LN metastasis, using χ(2) test. Significant factors were extracted for further analysis, carried out using a logistic regression method. Furthermore, lymph node metastasis was evaluated for any independent contribution to No. 10 LN metastasis, using the same methods. The cumulative survival rate was calculated using the Kaplan-Meier method. The significance of any difference between the survival curves was determined using the Cox-Mantel test, and any difference was considered significant at the 5% level. RESULTS: From the variables considered to be potentially associated with No. 10 LN metastasis, age, depth, invasion of lymph vessel, N factor, the number of lymph node metastasis, Stage, the number of sites, and location were found to differ significantly between those with metastasis (the Positive Group) and those without (the Negative Group). A logistic regression analysis showed that the localization and Stage were significant parameters for No. 10 LN metastasis. There was no case located on the lesser curvature in the Positive Group. The numbers of No. 2, No. 3, No. 4sa, No. 4sb, No. 4d, No. 7, and No. 11 LN metastasis were each found to differ significantly between the Positive Group and the Negative Group. A logistic regression analysis showed that No. 4sa, No. 4sb, and No. 11 LN metastasis were each a significant parameter for No. 10 LN metastasis. There was no significant difference in survival curves between the Positive Group and the Negative Group. CONCLUSION: Splenectomy should be performed to dissect No. 10 LN for cases which have No. 4sa, No. 4sb or No. 11 LN metastasis. However, in cases where the tumor is located on the lesser curvature, splenectomy can be omitted.

Suppressive effect of bevacizumab on peritoneal dissemination from gastric cancer in a peritoneal metastasis model.

PURPOSE: Vascular endothelial growth factor (VEGF) has been reported to enhance vascular permeability and angiogenesis in the abdominal wall, thereby contributing to peritoneal dissemination with malignant ascites. We conducted this experimental study to find out if bevacizumab, a humanized monoclonal antibody against VEGF, had a suppressive effect on peritoneal dissemination from gastric cancer, in an experimental nude mouse model of peritoneal metastasis. METHODS: Each mouse was treated with a single intraperitoneal (i.p.) injection of bevacizumab. Five mice were killed, and we measured their body weight, the mean number of tumor nodules, and the volume of ascites. We also extracted retroperitoneal tissues for histological examination, to count the frequency of mitosis, and to calculate the mitotic index. Another five mice were monitored until death, and their mean survival duration was calculated. RESULTS: The volume of ascites and the mitotic index were significantly lower in the therapy group than in the nontherapy group (P = 0.042 and P < 0.01, respectively). The survival curve of the therapy group was significantly higher than that of the nontherapy group (P = 0.005). CONCLUSION: Bevacizumab may suppress peritoneal dissemination from gastric cancer.

Malignant potential of gastrointestinal stromal tumor of the stomach.

Here, we report the Ki-67 Labeling Index, the expression of c-kit, p53, bcl-2, and apoptosis in 11 gastrointestinal stromal tumors (GISTs). The Ki-67 Labeling Index in the malignant GIST group was higher than that in the benign group. The Ki-67 Labeling Index in the p53-positive cases was higher than that in the p53-negative cases. The Ki-67 Labeling Index in the C-kit-positive group was higher than that in the C-kit-negative group. The bcl-2 expression was not correlated with potential malignancy. The apoptotic count in the bcl-2-positive cases was higher than that in the bcl-2-negative cases. The Ki-67 Labeling Index, the p53 overexpression, and the C-kit expression were useful in predicting the potential malignancy.

[Therapeutic experience of S-1 plus other drug combination therapy for synchronia multiple liver metastases of gastric cancer].

A treatment of multiple liver metastases of gastric cancer is very hard and its prognosis is extremely poor. At this time, we reviewed an efficacy of the therapeutic experience case with a new anticancer agent. The treatment was performed on nine cases of synchronia multiple liver metastases of gastric cancer since the new anticancer agent was introduced to the treatment. All of the 9 gastric cancer cases were diagnosed as being resectable other than ones with metastases to the liver, or a primary tumor resection was performed on the cases. The 1st line chemotherapy regimen was a combination of S-1+CDDP intra-arterial injection. The 2nd line chemotherapy regimen was S-1+CPT-11 intra-arterial injection. Furthermore, the 3rd line chemotherapy regimen was an administration of paclitaxel. There were no adverse events, such as hematotoxicity and non-hematotoxicity, that were greater than grade 3 during the duration of chemotherapy. Hence, we could continue the treatment regimen on all of the cases. The tumor responses for all of the cases were judged to be stable disease (SD). The best overall responses for all of the cases were judged to be progressive disease (PD). A median survival time (MST) of the treatment was 16 months, and that was significantly improved from 5.5 months, the regimen without a new anticancer agent (p=0.002). An ambulatory treatment was capable with the QOL in all of the cases. In conclusion, the tumor response did not show on the imaging, but it could be evaluable when there was an efficacy in the treatment that would support a daily life of patient.

[A resected case of advanced gastric cancer after treatment with low-dosage TS-1].

We report a case of advanced gastric cancer that responded well to low-dosage TS-1. A 72-year-old woman was diagnosed as having unresectable advanced gastric cancer with ascites and hydronephrosis in the right kidney. She was treated with chemotherapy using a low-dosage of TS-1 (80 mg/body/day) administered perorally for 4 weeks followed by a drug-free 2 weeks, in six-week cycles. However, she developed weight loss, appetite loss, and stomatitis. We therefore reduced the dosage of TS-1 from 80 mg/body/day to 60 mg/body/day. The ascites and hydronephrosis gradually improved during the following 3 months, whereupon she could undergo total gastrectomy. The postoperative findings showed no ascites and no peritoneal dissemination. The postoperative pathological findings showed that the cancer cells were localized to within the mucosa, and there were no cancer cells in the greater and lesser omentum. Three weeks after the operation, TS-1 was resumed at 60 mg/body/day. However, 3 months later,ascites and metastasis to the abdominal skin developed, and she died 9 months after the operation.

[Conventional chemotherapy combined with the repetitive immune cell transfer for patients with refractory advanced gastric cancer].

In order to take advantage by both the anticancer effects and reconstruction of antitumor immunity, we compared the feasibility of a combination of CTL transfer and chemotherapy (ChT) for patients (pts) with malignant ascites due to carcinomatous peritonealitis of refractory gastric cancer to that of ChT only and/or cellular immunotherapy after failing ChT. A total of 22 pts, 8 underwent only conventional ChT (Group A), 6 performed cellular IT after failing ChT (Group B) and 8 underwent combination therapy (Group C), were enrolled in this retrospective study. ChT was based on conventional conditioning regimen with a standard dose for gastric cancer cases: S-1 (80-120 mg/body) plus paclitaxel (60-80 mg/m2), or CPT-11 (70-80 mg/m2) plus CDDP (80 mg/m2). Autologous tumor cells stimulated with T lymphocytes (AuTL), a kind of CTL, were generated ex vivo from peripheral blood lymphocytes over a two-week co-culturing process with autologous tumor cells separating from the ascites. IT was performed for pts of Group B and C. AuTLs were administered twice prior to ChT for pts of Group C, and were injected 1 x /2 weeks directly into the peritoneal cavity. The treatment was repeated at least three cycles with one-week interval. The mean survival period of Group A, B and C was 8.4, 5.2 and 11.3 months, respectively, and 1 pt in Group A and 3 pts in Group C survived over one year. Adverse events related to both of the ChT and AuTL transfer at all doses were minimal. Ascites had decreased or disappeared in 8 pts in this study. Lymphocytes of ascites were evaluated for cytokine production and subset of CD4+CD25+ T cell before the treatment, and after 3 treatments. The group C pts had increased IFN-gamma and IL-12 production with no TGF-beta1 responses by their ascites after 3 treatments. In contrast, the group A and B had no IFN-gamma, IL-12 or TGF-beta1 responses. These data show that combination therapy of CTL transfer and ChT is a feasible option for patients with refractory peritoneal carcinomatous of gastric cancer without serious adverse events. Although it depends on each mechanism of IT and ChT, a more stringent evaluation of CTL transfer combined with ChT for refractory gastric cancer should be performed.

Clinical examination of the water-soluble vitamin levels in blood during peripheral parenteral nutrition.

The water-soluble vitamin (included vitamin B1, B6, B12 and C) preparations are not always replenished when peripheral parenteral nutrition (PPN) is used in Japan. We evaluated the need for administration of vitamins preparation during PPN, and involved analysis of the blood levels of water-soluble vitamins in patients receiving perioperative PPN before and after gastrectomy. Patients were examined as two set of groups as follows; 18 patients who did not receive water-soluble vitamin preparations during PPN, the Unsupplemented Group, and 22 patients who received such preparations during PPN, the Supplemented Group. Consequently, in the Unsupplemented Group, the blood vitamin B1 level during the early postoperative period was significantly lower than the preoperative level, but in the Supplemented Group, it was significantly higher than the preoperative level. In the Supplemented Group, the blood vitamin B12 level during the early postoperative period was markedly higher than the preoperative level. And in both groups, the blood vitamin C level remained below the lower limit of the criterion range throughout the perioperative period. These results suggested that administration of water-soluble vitamins during PPN was needed to avoid potential vitamin deficiencies after surgery and to prevent a potential onset of severe metabolic complications from any deficiencies.

[Peritoneal dissemination of scirrhous type 4 gastric cancers].

We examined 198 cases of primary scirrhous type 4 gastric cancer at our department from 1984 to 2003. Of these, 139 cases underwent gastrectomy. The essential cause of inoperability was peritoneal dissemination with malignant abdominal abscises. The incidence of peritoneal dissemination was 48.2% of all resected cases. The 5-year survival rate of all resected cases was 12% and that of non-resectable cases was 0%. One of the 59 nonresectable cases who responded remarkably to treatment by TS-1/paclitaxel combination chemotherapy obtained survival of 12 months. Six cases with peritoneal dissemination were treated by chemotherapy with cisplatin and etoposide infused intra-peritoneally and 2 of them were diagnosed as P 0 after 4 weeks. One case with type 4 gastric cancer who had right hydronephrosis and malignant abdominal ascites underwent curative resection after successful treatment with TS-1. We have selected the way of conventional chemotherapy for inoperable type 4 gastric cancers, but the prognosis is still poor. It is thought necessary to improve survival by newly developed anticancer agents such as TS-1, etoposide and taxanes. Immuno-cellular therapy with autologous tumor cell stimulated lymphocyte may be examined as a neo-adjuvant therapy as well as chemotherapy.

VEGF significance in peritoneal recurrence from gastric cancer.

BACKGROUND: In gastric cancer, the management of peritoneal dissemination in the Peritoneal cavity is extremely important; however, peritoneal dissemination in the final stage of gastric cancer remains untreatable. Peritoneal dissemination involves several steps, including tumor-cell attachment, invasion, and growth in the peritoneum. Many cytokines, growth factors, matrix metalloproteinases (MMPs), and angiogenic factors play important roles in these steps. So far, few studies have investigated the correlation, if any, between peritoneal dissemination and the angiogenic factor, vascular endothelial growth factor (VEGF). METHODS: Immunohistochemical staining, using the avidin-biotin peroxidase complex method, was performed on slides of surgical specimens from 40 patients with stage II gastric cancer with serosal invasion, who underwent surgery at our hospital between 1990 and 2000. Anti-human VEGF rabbit polyclonal IgG was used as the primary antibody. VEGF expression was classified in one of four categories depending on the percentage of tumor-cell staining (P). VEGF expression was also classified in one of three categories depending on the staining intensity (I). The VEGF expression score was calculated as P x I. RESULTS: There were ten patients with peritoneal recurrence. Of these, seven had macroscopic type-4 scirrhous-type gastric carcinoma. In the immunohistochemical study, the VEGF score of patients with peritoneal recurrence was 9.40 +/- 2.46; on the other hand, that of patients without peritoneal recurrence was 3.47 +/- 2.36. The VEGF score of patients with peritoneal recurrence was significantly higher than that of patients without peritoneal recurrence. In patients with macroscopic type 4, the VEGF score of those with peritoneal recurrence was 9.14 +/- 2.19, while on the other hand, that of the patients without peritoneal recurrence was 3.80 +/- 3.03. The VEGF score of these patients with peritoneal recurrence was significantly higher than that of those without peritoneal recurrence. The survival rate in the VEGF low-expression group was significantly higher than that in the VEGF high-expression group. Multivariate analysis showed that the VEGF score was a significant parameter of peritoneal recurrence. CONCLUSION: These results suggested that VEGF was correlated with peritoneal metastasis from gastric cancer, and that VEGF was a useful indicator of peritoneal recurrence.

Cisplatin resistance and transcription factors.

Cisplatin is one of the most potent and widely used anti-cancer agents in the treatment of various solid tumors. However, the development of resistance to cisplatin is a major obstacle in clinical treatment. Several mechanisms are thought to be involved in cisplatin resistance, including decreased intracellular drug accumulation, increased levels of cellular thiols, increased nucleotide excision-repair activity and decreased mismatch-repair activity. In general, the molecules responsible for each mechanism are upregulated in cisplatin-resistant cells; this indicates that the transcription factors activated in response to cisplatin might play crucial roles in drug resistance. It is known that the tumor-suppressor proteins p53 and p73, and the oncoprotein c-Myc, which function as transcription factors, influence cellular sensitivity to cisplatin. So far, we have identified several transcription factors involved in cisplatin resistance, including Y-box binding protein-1 (YB-1), CCAAT-binding transcription factor 2 (CTF2), activating transcription factor 4 (ATF4), zinc-finger factor 143 (ZNF143) and mitochondrial transcription factor A (mtTFA). Two of these-YB-1 and ZNF143-lack the high-mobility group (HMG) domain and can bind preferentially to cisplatin-modified DNA in addition to HMG domain proteins or DNA repair proteins, indicating that these transcription factors may also participate in DNA repair. In this review, we summarize the mechanisms of cisplatin resistance and focus on transcription factors involved in the genomic response to cisplatin.

Surgery and clinicopathological features of gastric adenocarcinoma involving the esophago-gastric junction.

To clarify the optimal operative procedure for gastric adenocarcinoma involving the esophago-gastric junction (EGJ), we investigated 49 cases with an upper gastric cancer invading the esophagus who underwent surgical treatment in our department during the period from 1991 to 2000. According to Siewert's classification, there were 21 cases with a type II tumor, and 28 cases with a type III tumor. Twenty-five cases underwent surgery through an abdominal approach only. The remaining 24 cases were operated on via a left thoraco-abdominal approach. Eight (33%) of 24 cases who underwent extended lymphadenectomy through a left thoraco-abdominal approach had lower mediastinal lymph node metastasis. Metastasis was observed in cases with cancer invasion more than 2 cm from the EGJ. There were 6 cases with a T1 tumor, 6 with a T2 tumor, 27 with a T3 tumor, and 10 with a T4 tumor. Incidences of lymph node metastasis were 0% for T1, 67% for T2, 81% for T3, and 80% for T4. Proximal gastrectomy was performed in 6 cases at the early stage and in 10 cases at the advanced stage with distant metastasis (M1). Total gastrectomy was done in 33 cases at the advanced stage, and 3 of these 33 cases had metastasis to the parapyloric lymph nodes. We performed combined resection of the body and tail of the pancreas and the spleen in 7 cases. One of these 7 cases had direct invasion to the pancreas and 6 cases had remarkable metastasis to the lymph nodes along the splenic artery. Splenectomy preserving the pancreas was done in 24 cases. The incidences of metastasis of the lymph nodes along the splenic artery and the splenic hilum were 25% and 17%, respectively. We performed partial resection of the diaphragm surrounding the esophageal hiatus in 15 cases through a left thoraco-abdominal approach. Six cases had metastasis to the diaphragm and nine cases had direct invasion to the diaphragm. Tumors were stage I in 8 cases, II in 5 cases, III in 13 cases and IV in 23 cases, and the curability was categorized as A in 8 cases, B in 20 and C in 21. The overall 5-year-survival rate was 25%, and the rates according to cancer stage were 86% for stage I, 40% for stage II , 21% for stage III and 0% for stage IV. The 5-year survival rates of cases at stage II and III were 33% for cases using the left thoraco-abdominal approach and 28% for cases with the abdominal approach. Based on these results, we recommend distal esophagectomy with total gastrectomy, and occasional combined resection of the spleen and the diaphragm through a left thoraco-abdominal approach for advanced gastric adenocarcinoma involving the EGJ.

[Gastric cancer with liver metastasis effectively treated by intra-hepatic arterial infusion].

The prognosis of gastric cancer with liver metastasis is very poor. Because many gastric cancers with liver metastasis have multiple metastatic tumors in the liver, and the indication for surgical resection is rare. Moreover, the non-curative factors of many cases are not only liver metastasis but also are lymph node metastasis and peritoneal dissemination. However, some authors have reported gastric cancer with liver metastasis was treated effectively by intra-hepatic infusion of an anti-cancer drug. In this article, we report three cases of gastric cancer with liver metastasis that are treated effectively by intra-hepatic arterial infusion of an anti-cancer drug. There were no non-curative factors except liver metastasis. The first was a H3 case treated effectively by intra-hepatic arterial infusion of 5-fluorouracil (5-FU), mitomycin C (MMC) and peroral administration of 5-FU. The metastatic liver tumors had disappeared in 14 weeks. However, the patient eventually died of liver and brain metastases in 7 months after the therapy. The second was a H2 case treated effectively by intra-hepatic arterial infusion of CDDP and peroral administration of 5'-DFUR and PSK. The metastatic liver tumors had disappeared in 4 months, and the patient is still alive without recurrence in 35 months after surgery. The third was a H2 case treated effectively by intra-hepatic arterial infusion of cisplatin (CDDP) and peroral administration of TS-1 and PSK. The size of metastatic nodules had increased, and Virchow lymph node metastasis had appeared in 28 months after surgery. The patient eventually died in 32 months after surgery. These results suggested that intra-hepatic arterial infusion of CDDP with peroral administration of TS-1 or 5'-DFUR was an effective therapy for gastric cancer with liver metastasis.